Dental handpiece



s. lair.,BROOK-s.V vDENTAL HANDPIEGE.

-(No Model.)

Patented Apr. 10, 1894.

No. 518,175.A

NME

ma NATIONAL u'mcalAPHma cmAPANY.

vumumarom n. c.

Maf/fav.' Mm mwt,

NIfIEl lirfi;

PATENT Ferca. I

STEPHEN H. BROOKS, OF NEW YORK, N. Y., ASSIGNOR TO EDWARD A. PEIROE, OF SAME PLACE, AND J. OTIS COX, OF BROOKLYN, NEW YORK.

DENTAL HANDPIECE.

SPECIFICATION forming part of Letters Patent No. 518,175, dated April 10, 1894.

Application tiled October 31, 1893. Serial No. 489,610. (No model.)

To all whom it may concern:

13e it known that I, STEPHEN H. BROOKS, a citlzen of the United States, and a resident of the city, county, and State of New York, have invented certain new and useful `Improvements in Dental Handpieces, of which the following is a specification.

My invention has reference to hand-pieces or tool-carriers for dental engines, and particularly to such hand-pieces as are provided with spring jawed chucks for firmly securing therein the shanks of the tools, which Shanks are generally made cylindrical and of about the same diameter.

The principal purposes of my invention are to provide adental hand piece of simple, compact and substantial construction, capable of -rmly securing the shankpf the tool within a proper chuck in such a manner as to insure the revolving of the tool by means of the iiexible shaft of the dental engine and to enable the operator to promptly remove a tool from the hand piece, or toinsert a tool in the same without arresting the movement of the engine. I accomplish these and other useful purposes by the means hereinafter specified and particularly set forth in the claims.

'In the accompanying drawings, Figure 1 represents a longitudinal vertical section of a hand piece constructed according to my invention, the tool being shown to be inserted in the same and to be firmly gripped by the tool-chuck. Fig. 2 represents such a section of the principal part of the hand piece showing the position of its parts after the tool has been withdrawn therefrom; while Fig. 3 shows.

a vertical cross-section of the device along line 3, 3 in Fig. 2. I

Corresponding figures throughout the different views refer to corresponding parts.-

The outer casing of the hand piece consists of a handle section 4, a'shank section 5, and anintermediate section 6, section 6 being attached to section 4 by screw-thread and to section 5 by means of a swivel joint, in the usual manner. The rear inner part of the shank section is providedwith screw-thread for the purpose of attaching thereto a ilexible sheath as is usually employed in dental engines for the purpose of protecting thereby a flexible power conveyer .which communithat the rear end of1such spindle is made to abut againstthe inner front end of casing section 6 while the front end of the spindle engages with a propershoulder in the interior of handle section 4 of the casing, the screw-thread between handle sections 4 and 6 thus permitting to enforce proper contact between the ends of the spindle and its abutments.

10 is a double chuck for receiving the shank 11 of a dental tool, spring jaws 12, 12 being provided on its front as well as its rear end. The outerend surfaces of such chuck are made tapering, the front surfaces to approximately correspond with the adjoining interior surfaces of the spindle, and the rear surfaces to so correspond with the inner front "surfaces of a hollow clamping plug 13.

14 is a bar abutting against the rear end of plug 13. Parts l0, 4'13 and 14 jointly and separately are capable of sliding longitudinal movement within the body of spindle 7 in such a manner that forward movement of bar 14 will produce close contact of double chuck 12 with clamping plug 13 as well as with the aforesaid tapering surfaces in the interior of the spindle, and, if the shank of a tool has previously been inserted in the chuck its front jaws as well as its rear jaws will thereby be forced to bind upon and to firmly grip such shank. On the other hand, if the forward pressure applied tobar 14 be made to cease, the spring power inherent to the jaws 12 of the chuck will assert itself by compelling a rearward movement of plug 1-3 IOO ing device and driving shaft 8. Its front is provided with a wedgin g surface 16 of a slope corresponding with another slope on the rear surface of the locking device where the saine comes in contact with such wedgiug surface. Latch 15 is adapted to slide along such slope and within a suitable channel cut in said locking device, at right angles to the spindle, proper guiding slots being provided for such purpose in the latter.

17 is a sleeve mounted on spindle 7 so as to slide thereon and fitting the interior surface of handle section 4. It is provided with a wedging surface 18 adapted to engage with the upper surface of latch 15, which upper surface I preferably construct parallel to it. The lower extremity of the latch which extends outside of the spindle and also through a proper slot in said 4slide may be provided on its face with a bevel conforming substantally with a bevel 19 at the front end of such s ot.

20 is an annular groove in the rear end of sleeve 17.

2l is an outer sleeve mounted on section 4 of the casingand capable of sliding thereon.

22is a pin provided with screw-thread where it passesthrough said outer sleeve and havingits inner end extending into annular groove 2O in such a manner as to compel the two sleeves to slide forward and backward together, while permitting the inner sleeve to rotate with the spindle, without imparting its revolving motion to the outer sleeve.

The operation of the device is as follows: When it is desired to clamp the tool shank within chuck 10 sleeve 21 and with it pin 22 and inner sleeve 17 are moved forward until they assume the positions shown in Fig. l, the upper slope on the latch coacting meantime with the corresponding slope on such sleeve, so as to force the latch downward and at the same time by means of its wed ging surface 16 compelling the forward movement of the tool lockingdevice and the gripping of the tool shank, while the reverse movement of the two sleeves will permit the upward movement of the latch, and such upward movement will be enforced by the inherent spring power of the tcol chuck compelling a backward movement of clamping plug '13 and bar 14. If, however, for any reason binding of these parts upon each other and upon the spindle should oocur, so as to retain the latch in the `position shown in Fig. 1, said latch will be freed and will be forced out of its locking position whenever edge 19 strikes its lower extremity.

23 is a slot in the upper surface of sleeve 17 to permit the insertion through it of the latch when the hand piece is being put totogether.

l have found in practice that it is best to make the sloping contact surfaces between the latch and the tool locking device very small as compared with the full cross-section of the latter, in order to insure the prompt upward movement of the latch when the tool shank is to be withdrawn and for Suchparpose I reduce bar 1-1: in depth where it adjoins the face of the latch as shown more particulaily in Fig. l.

Vhile the drawings show my preferred form of construction, I do not wish to confine myself to the details illustrated therein. T hus it will be seen that plug 18 and bar 14 might be consolidated, as the principal reason for making them separate is, that I am thereby enabled to insert washers between these parts whenever it becomes desirable to do so in order to compensate for their wearing upon the latch and the chuck. i'

I prefer to employ a double chuck, as 10, in order to obtain the benefit of two sets of spring jaws in clamping the tool and also in forcing upward the latch when the tool shank is to be withdrawn, but it will be seen that any other proper form of a chuck or of a tool locking device, which will accomplish these objects, may be employed instead. Clamping plug 13 is shown to be hollow so as toaccommodate the rear extremity of the tool shank which is generally provided with notches intended to make it capable of being secured in other dental hand pieces employing latches engaging directly with the tool shank.

By employing a sliding latch or wedge for actuating the tool locking device I am able to obtain a gradual forward movement of the locking device, at a speed at all times proportionate with the speed of the slide actuating it and to exert great forward pressure upon the tool locking device and consequently strong gripping action of the chuck upon the tool shank. A further and great advantage is that in such a hand piece only sliding contact takes place between the parts of the mechanism operating the locking device, the use of all pivots and of fulcrums for levers which would tend to cause binding` action and rapid wear of the parts being thus done away with.

I claim as new and desire to secure by Letters Patent-- 1. In a dental hand piece, the combination with the casing, of a spindle, a splitor springjawed tool locking device, a wedge adjusted to slide transversely to the spindle and along the surface of such locking device and means for enforcing operative contact between the wedge and said locking device, suchwedge adjusted to move the tool-locking device endwise for the purpose of clamping the tool, and to receive motion from the tool locking device when such means for enforcing operativecon tact cease to operate, substantially as set forth.

2. In a dental hand piece, the combination with the casing, of a spindle fitted to rotate therein, a split clamp tool locking device, a sliding wedge, proper surfaces for guiding it l'OO lIO

transversely to the spindle, and means for moving it along such guides, substantially as set forth.

3. In a dental hand piece, the combination with the casing, of a. spindle, a split clamp tool locking device, a sliding wedge, proper surfaces for guiding it, and a slide for compelling its movement and provided with a sloping surface adjusted to engage with the wedge, substantially as set forth.

4. In a dental hand piece, the combination with the casing, of a spindle titted to rotate therein, a split clamp tool locking device, a sliding wedge, proper surfaces for guiding it transversely to. the spindle, and a slide having two surfaces for engaging with the Wedge whereby such Wedge may be moved in opposite directions, substantially as set forth.

5. In a dental hand piece, the combination with the casing, of a spindle, a split clamp tool locking device, a Wedge, a channel in the tool locking device wherein the wedge slides and means for moving the wedge along such channel substantially as set forth.

6. In adental hand piece, the combination with the casing and spindle, of split clamp tool locking device 12, 13, 14, connecting bar 8, sliding wedge 15 inner slide 17, outer slide 2l and intermediate pin 22, substantially as set forth. Y,

In testimony that I claim the foregoing as my invention I have signed my name, in presence of two witnesses, this 27th day of October, 1893.

STEPHEN H. BROOKS. Witnesses:

CEAS. L. HoRAcK, ARTHUR H. SYMoNs. 

